Because the libc is calling it again based on what has been passed as argument and what was received as return value. Here is one example https://gist.github.com/gkos/5479135. I don't really know if this code is working since I made it a long time ago.

Regards,

2016-10-04 12:05 GMT-03:00 Greg KH <greg@kroah.com>:

On Tue, Oct 04, 2016 at 10:58:16AM -0400, Kenneth Adam Miller wrote:
> I have a character device that I am calling write on and which is succeeding,
> but which is repeatedly executing. I have hard coded the return value to one,
> so I don't think the userland standard library is retrying but I could be
> wrong. Can anybody tell me why write would be re-executed by the kernel and how
> to fix it? I dont actually copy_from_user, I just need this in order to signal
> kernel land.

Do you have a pointer to your code somewhere? This is a very common bug
that people have...

thanks,

greg k-h

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

"Do or do not. There is no try"
Yoda Master